Engine COMP sometimes glitches and switches outputs when running at different FPS than main project

Hey all, I’ve got a weird bug in a recent project. When my Engine COMPs are running at a different FPS than the main project, sometimes the outputs of the Engine COMP glitch and get switched - anyone know what might cause this? Included is a project and a TOX that have this behavior on my machine…

To emulate this, I made multiple Engines that are being hogged, while the main process is running at a smooth 60 fps.

I’m on Windows laptop, GTX 2070 Max-Q on the latest stable release… (2021.12380).

engineFramSwitchBug.zip (5.8 KB)

Here’s a screenshot to show what I mean:

Thanks, was able to reproduce and have logged this bug.

Thanks @ben … any workarounds in the meantime that you might know of? :slight_smile:

Sorry, this is a pretty weird performance bug/issue. You could make it just 1 output with the images side-by-side and then divide them on the outside (crop etc) but that is a dirty hack. :wink:

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Depending on the context, I prefer to use spout instead of the built in TOP transfer - it very much depends on the use case though!

You will probably have some issues, but a different set of issues that might be better for your implementation :sweat_smile:

Actually, I just had this happen for the first time today with 2 engines, nothing out of the ordinary, other than a single frame of large cook time during a video load within one of the engines. I would have to verify, but this might actually be happening only on the TOP viewers, and not downstream? I’ll post if I can replicate consistently.

This issue is fixed in 2021.14360 - thanks for the report.

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Sorry all - it turns out there was one problem hiding under another one here, and this isn’t completely fixed in 2021.14360.

We have a fix for this now @maaark. We wont be posting a new Official build for a month or so so here’s a link to an internal build with this fix.


Thanks so much, Ben! We have since found a workaround, but might implement it again in a future update :slight_smile:

@maaark Ok, great to hear. It would be cool to know if you case was fixed definitely, we used your example file to test with but maybe not the same as your real-world project.

Official build 2021.15020 was just posted with this fix.

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